Galapagos Hawk: Demographic and Social Effects in a Changing Environment

The Galapagos Hawk (Buteo galapagoensis) is endemic to the Galapagos Islands, where it is the top predator and only resident diurnal raptor. On most islands, Galapagos hawks form polyandrous breeding groups with one female with up to eight males. Before entering a breeding group, individuals spend 3-4 years as non-breeding floaters. I studied the hawks on Santiago Island, where introduced goats had been recently eradicated, leading to drastic changes in the ecology of the island. Using mark-recapture procedures, we assessed the size of the juvenile component of the population over time. In addition, using software MARK with a 12-year demographic database on this population to model annual survivorship of breeding adults. I also used this database as well as current observations to describe natal dispersal patterns and patterns of floater sociality. The population size of the floater fraction of the population declined at the end of the goat eradication program, with an apparent disappearance in 2007 and 2008, and an apparent recovery in 2009. Territorial adult survivorship probability is a function of sex, body size, territory vegetation type and breeding group size per year, but the relative importance of these factors changes between years. The lowest annual adult survivorship through the 12 years monitored was 2005-2006, the final year that the goats were eradicated. In the component focusing on juvenile behavior, I found that individuals do tend to disperse to territories neighboring their natal territories (p\u3c0.05), but they showed no statistical preference for territories with similar vegetation (p\u3e0.05). Individuals in the four-year juvenile period do not form stable coalitions with particular individuals even though they are often highly aggregated. The eradication of goats from Santiago Island had an effect on the Hawk’s population; further monitoring is needed to better understand possible long term effects still to be seen and better understand the relationship of survivorship estimates with possible unaccounted variables such as prey abundance

Population Genetics of Island Endemics: Neutral and Major Histocompatibility Loci

Island archipelagoes are ideal for the study of microevolutionary forces due to their multiple, closely related but geographically disjunct populations. I used both neutral and major histocompatibility complex (MHC) loci to determine the population genetic structures of bird species endemic to the Galapagos Islands. MHC molecules recognize foreign pathogens in the body, and these loci are known for their high degree of genetic variability maintained by natural selection. Small island populations are predicted to have reduced genetic variability due to the effects of genetic drift; however, selection may be strong enough to prevent the loss of variability at MHC loci. First, I characterized neutral genetic structure in the Galapagos hawk (Buteo galapagoensis). Analyses of both neutral nuclear VNTR (Chapter 1) and mitochondrial (Chapter 2) loci showed low within-population variability but high between-population differentiation. In Chapter 3, we found that smaller, more inbred populations had birds with higher louse loads and, in general, lower and less variable natural antibody titres than the larger, more genetically variable hawk populations. Chapter 4 presents MHC work done on the Galapagos penguin (Spheniscus mendiculus), a seabird whose breeding colonies experience population bottlenecks associated with El Niqo events. Galapagos penguins had low variability, having only three MHC alleles which differed by only a few base pairs. MHC work on the Galapagos hawks (Chapter 5) revealed similarly low variability. Galapagos hawks had fewer and less divergent alleles than the Swainson?s hawk, their closest mainland relative. The MHC diversity in both the Galapagos species was lower than in the mainland species, indicating that genetic drift has had an overwhelming effect. Lastly, in Chapter 6, I characterized the neutral population genetic structure of six Galapagos mockingbird (Mimus spp.) populations. Genetic variability increased with island area and we found a pattern of isolation by distance, both indicating the influence of genetic drift. Significant levels of genetic and morphological differentiation existed among all six populations, though morphological distances were smaller between islands of similar area suggesting the influence of natural selection

Dinámica poblacional del Gavilán de Galápagos (Buteo galapagoensis) en la isla Santa Fe: efectos del clima, estructura del hábitat y presencia-ausencia de cabras sobre la reproducción y sobrevivencia

El gavilán de Galápagos es el único rapaz diurno que habita en ocho islas del archipiélago. Está catalogado como vulnerable por la UICN debido a que sus poblaciones son pequeñas, aisladas genéticamente y con poca migración entre islas. Las variaciones climáticas en Galápagos, especialmente relacionadas con el fenómeno de El Niño, han afectado varias poblaciones animales y vegetales. Utilizando información de ocho años de censos en la isla Santa Fe, comparé los cambios en el área y utilización de los territorios por parte de gavilanes adultos. Analicé los patrones de sobrevivencia usando modelos de captura-marca-recaptura en el programa Mark y evalué la contribución de variables ambientales con retraso de tiempo y el tipo de hábitat en la dinámica poblacional del gavilán. Los resultados muestran que para los 19 territorios encontrados, el área se ha mantenido constante para la mayoría, excepto dos territorios poliándricos que ampliaron su área en 2007, ocupando áreas que permanecieron vacíos. Este resultado podría estar relacionado con un bajo número poblacional. La sobrevivencia de juveniles fue entre el 43 % y 87 %, menor que la sobrevivencia de adultos que fue entre 61 % y 92 %. La sobrevivencia de adultos en los años 2001, 2007 y 2009 fue alrededor del 90 %, mientras que en los años 2010, 2011 y 2012 se registraron sobrevivencias más bajas, entre 60 % y 80 %. Los resultados sugieren que el índice de ENSO podría ser un buen predictor de la sobrevivencia de gavilanes adultos en Santa Fe, así como también la edad a la que fueron marcados y el tipo de hábitat donde se ubican los territorios. La precipitación en los primeros meses del año mostró estar relacionada positivamente con la reproducción, posiblemente como consecuencia del aumento en la cantidad de alimento disponible. No encontré relación entre el tamaño poblacional y la presencia o ausencia de cabras en Santa Fe, pero no podemos hacer ninguna conclusión dada la escasez de datos disponibles para los años con cabras. Los resultados apoyan la predicción que la sobrevivencia de los gavilanes en Santa Fe podría estar afectada positivamente por eventos climáticos cálidos y negativamente con eventos fríos. Disminuciones en los valores de sobrevivencia podrían llevar a un decrecimiento poblacional, por lo que las estrategias de conservación deben enfocarse en mantener valores altos de sobrevivencia en adultos

Rats, Mice, and People: Rodent Biology and Management

Farm Management,

Invasive Birds: Global Trends and Impacts

This 381-paged book covers the biology, ecology, impact and management of 34 common alien invasive species, with reviews on the history and context of avian introductions and invasions in five major regions (Oceania, Africa, Europe (including the Middle East, Asia and South America)), as well as management challenges and the potential of citizen science for monitoring alien birds. The book pitches at the introductory level and is ideal for readers to gain a quick and comprehensive view of the current status of global avian invasions. It has brought the records and research of avian invasion one step ahead of other alien invasive animal taxa. Many chapters contain distribution maps and data tables on the diet and morphology of the species, providing a good reference for the species and its management issues. Each chapter also contains a rich list of references that could help readers dive further into the topic

Terrestrial Mammal Conservation: Global Evidence for the Effects of Interventions for terrestrial mammals excluding bats and primates

Terrestrial Mammal Conservation provides a thorough summary of the available scientific evidence of what is known, or not known, about the effectiveness of all of the conservation actions for wild terrestrial mammals across the world (excluding bats and primates, which are covered in separate synopses). Actions are organized into categories based on the International Union for Conservation of Nature classifications of direct threats and conservation actions. Over the course of fifteen chapters, the authors consider interventions as wide ranging as creating uncultivated margins around fields, prescribed burning, setting hunting quotas and removing non-native mammals.This book is written in an accessible style and is designed to be an invaluable resource for anyone concerned with the practical conservation of terrestrial mammals.The authors consulted an international group of terrestrial mammal experts and conservationists to produce this synopsis. Funding was provided by the MAVA Foundation, Arcadia and National Geographic Big Cats Initiative.Terrestrial Mammal Conservation is the seventeenth publication in the Conservation Evidence Series, linked to the online resource www.ConservationEvidence.com. Conservation Evidence Synopses are designed to promote a more evidence-based approach to biodiversity conservation. Others in the series include Bat Conservation, Primate Conservation, Bird Conservation and Forest Conservation and more are in preparation. Expert assessment of the evidence summarised within synopses is provided online and within the annual publication What Works in Conservation

Terrestrial Mammal Conservation

"Terrestrial Mammal Conservation provides a thorough summary of the available scientific evidence of what is known, or not known, about the effectiveness of all of the conservation actions for wild terrestrial mammals across the world (excluding bats and primates, which are covered in separate synopses). Actions are organized into categories based on the International Union for Conservation of Nature classifications of direct threats and conservation actions. Over the course of fifteen chapters, the authors consider interventions as wide ranging as creating uncultivated margins around fields, prescribed burning, setting hunting quotas and removing non-native mammals. This book is written in an accessible style and is designed to be an invaluable resource for anyone concerned with the practical conservation of terrestrial mammals. The authors consulted an international group of terrestrial mammal experts and conservationists to produce this synopsis. Funding was provided by the MAVA Foundation, Arcadia and National Geographic Big Cats Initiative. Terrestrial Mammal Conservation is the seventeenth publication in the Conservation Evidence Series, linked to the online resource www.ConservationEvidence.com. Conservation Evidence Synopses are designed to promote a more evidence-based approach to biodiversity conservation. Others in the series include Bat Conservation, Primate Conservation, Bird Conservation and Forest Conservation and more are in preparation. Expert assessment of the evidence summarised within synopses is provided online and within the annual publication What Works in Conservation.